Pneumonia

What is pneumonia and what does cause it?

Pneumonia is an inflammation of the lungs caused by bacteria, viruses or fungi [1]. Infants, individuals older than 65 years and those with chronic diseases or impaired immunity are at greatest risk.

Pneumonia can be mild or severe. Properly treated pneumonia in otherwise healthy individuals has an excellent prognosis, but if untreated, especially in those with impaired immunity, it can be life-threatening. Pneumonia is a major cause of death all over the world [24].

Pathophysiology – How does pneumonia develop?

Microbes can reach the lungs by inhalation, aspiration (the entrance of solid or liquid material into the lungs, for example, during vomiting) or by blood, for example, in intravenous drug users or during blood infection or septicemia (septic pneumonia).

Microbes activate the immune cells (leukocytes, macrophages) in the lungs, which results in inflammation and fluid and pus accumulation in the air sacs (alveoli). Sometimes, inflammation occurs only in the spaces between the air sacs (interstitial space) without fluid accumulation within the air sacs.

Other Types of Pneumonia

Chemical pneumonia can be caused by inhalation of irritating chemicals

Eosinophilic pneumonia, which is not true pneumonia, because it is not an infection, but possibly an allergic reaction

Secondary pneumonia is a term for pneumonia that develops as a complication of some other disease, for example, post-viral pneumonia in a patient with the flu.

Opportunistic pneumonia is pneumonia that develops in individuals with impaired immunity, for example, due to treatment with steroids or chemotherapy, cancer or sickle cell anemia. Pneumocystis pneumonia (PCP) typically occurs in individuals with HIV/AIDS.

Hypostatic pneumonia can occur due to infection in less ventilated parts of lungs, mainly in older bedridden individuals.

Diagnosis

A doctor can make a diagnosis of pneumonia on the basis of your medical history, physical examination and investigations.

Physical examination:

Tapping parts of the chest (percussion) can provoke dull sounds.

Listening to the lungs by the stethoscope (auscultation) can reveal crackling sounds and decreased breath sounds.

Investigations:

Sputum (coughed up mucus) culture

Blood tests:

Blood culture

Immunoglobulins against viruses

Complete blood count (CBC)

Pleural fluid culture

X-ray: The diagnosis of pneumonia can be made only if white shadows are present on the film.

Pulse oximetry–a quick test to measure oxygen in the blood

Arterial oxygen saturation

Bronchoscopy can be done to detect eventual obstruction in the bronchi.

Treatment

In hospital: intravenous antibiotics, oxygen by mask [18] or in severe cases, mechanical ventilation that may require intubation or tracheostomy [8] NOTE: The insertion of breathing tube for mechanical ventilation by itself increases the risk of bacterial pneumonia [22].

Antibiotic-resistant bacteria, which are resistant to common antibiotics, should be treated with alternative antibiotics:

Viral pneumonia usually does not require any special treatment and it can heal on its own. If started early, antivirals (acyclovir, cidofovir, oseltamivir, palivizumab, ribavarin or zanamivir) may shorten the duration of pneumonia in some cases.

Fungal pneumonia can be treated by antifungals (itraconazole, amphotericin B).

Centrally acting anti-cough medicines may prevent you coughing up mucus properly, so speak with a doctor about using them.

Steroids. There is weak evidence about beneficial effects of corticosteroids in the treatment of pneumonia [12,13,14].

Exercises:

Make a deep breath, hold it for a while, then cough up mucus and spit it out. Repeat 10 times every hour during the day [10].

Tap your chest few times a day while lying with your head lower than your chest — this may help remove some mucus from your lungs [21].

There is insufficient evidence about the beneficial effects of vitamin C [15], essential oils [20], over-the-counter (OTC) cough medicines [19] and chest physiotherapy in children [16] or adults [17] in preventing or treating pneumonia.

Recovery Time/Prognosis

In otherwise healthy individuals, pneumonia, when treated properly, is usually a benign disease, which can last for few weeks and heal completely without complications [1]. Untreated atypical pneumonia can last for several months.

In infants, elderly and individuals with chronic diseases, pneumonia can be a serious illness, which can be deadly if not treated promptly.

Complications

Complications of pneumonia more likely occur in young infants, elderly and in individuals with diabetes, impaired immunity (HIV/AIDS) or liver cirrhosis (alcoholics) [4].